The present invention relates generally to medical and/or biological testing and devices for performing same, and more particularly, to a method and apparatus for analyzing minute amounts of nucleic acids for the presence of specific nucleotide sequences. Single-strand DNA probes are bound to specific regions of microchannels in a glass microchip device. Sub-microliter volumes of nucleic acid solutions, buffers and other reagents are transported through the channels under electrokinetic or hydraulic control. Hybridization of target nucleic acid sequences to complementary probes is detected using either fluorescent labels or intercalating fluorescent dyes.
Hybridization analysis is typically performed in microtiter plate wells or on planar surfaces that contain arrays of DNA probes. Chemical manipulations are required to bring about a hybridization test and to detect the results. These manipulations presently include washing or dipping planar arrays into the appropriate chemicals.
The aforementioned procedures suffer from many drawbacks. For example, they are wasteful of expensive reagents and limited sample volumes. Moreover, they are generally not compatible with efficient automation strategies and thus tend to be time consuming.
A continuing need exists for methods and apparatuses that limit the use of expensive reagents and priceless samples, while simplifying the overall procedures to require smaller samples and fewer processing steps.
An object of the present invention is to provide a method and apparatus for analyzing nucleic acids which simplifies chemical manipulations required to bring about a hybridization test when performing DNA diagnostics in biomedical, forensic, and research applications.
Another object of the present invention is to provide a method and apparatus for analyzing nucleic acids which minimizes the use of expensive reagents and limited sample volumes.
Another object of the present invention is to provide a method and apparatus for analyzing nucleic acids which avoids the necessity of pre-labeling a target DNA and increases the sensitivity of hybrid detection by reducing background fluorescence due to non-specific surface adsorption of labeled target DNA.
Still another object of the present invention is to provide a method and apparatus for analyzing nucleic acids which significantly extend the usefulness of hybridization diagnostics by allowing its application to much smaller samples and facilitating automated processing.
These and other objects are met by providing an apparatus for analyzing nucleic acids which includes a microchip having a microchannel structure formed therein, at least one portion of the microchannel structure having at least one site capable of affixing thereto a probe, and a plurality of reservoirs in communication with the microchannel structure for introducing at least one of, or a mixture of, a reagent, analyte solution, and buffer.
In another aspect of the invention, a method of analyzing nucleic acids includes bonding oligonucleotide probes to a microchannel formed in a microchip, adding target nucleic acids and fluorescent stains to the microchannel, and detecting hybridization by fluorescence staining of double-stranded DNA.
These together with other objects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, with reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like elements throughout.